Synthesis and characterization of a monoruthenium(III)-substituted Dawson polyoxotungstate derived by Br2 oxidation of the 1∶2 complex of ruthenium(II) and [α2-P2W17O61]10−. The reactivity of cis-[RuCl2(DMSO)4] as a ruthenium source

Abstract

Synthesis and characterization of the monoruthenium(III)-substituted Dawson polyoxotungstate K7[α2-P2W17O61RuIII(H2O)]·19H2O 2, expected to be an effective homogeneous oxidation catalyst precursor, is described. The reaction products of cis-[RuIICl2(DMSO)4] as the ruthenium source with mono-lacunary Dawson polyoxotungstate have been examined. By 5 h reaction of cis-[RuIICl2(DMSO)4] with K10[α2-P2W17O61] in ice-cooled, HCl-acidic aqueous solution, a water-soluble 1 ∶ 2-type diamagnetic ruthenium(II) complex, with formula K18[RuII(DMSO)2(P2W17O61)2]·35H2O 1, was unexpectedly obtained as an analytically pure, homogeneous tan-colored solid, in which two DMSO molecules are coordinated to the ruthenium(II) atom. By Br2 oxidation of 1, the 1 ∶ 1-type paramagnetic complex 2 was obtained as a black crystalline solid. Characterization of 1 and 2 has been carried out with complete elemental analysis, thermogravimetric and differential thermal analyses (TG/DTA), FT-IR, magnetic susceptibility measurements, cyclic voltammetry, UV-vis absorption and 31P and 183W NMR spectroscopies, as well as 1H and 13C NMR for 1.